As San Francisco faces a major citywide Muni slowdown on almost every bus route, the San Francisco Municipal Transportation Agency posted a public apology on its website to Muni riders Thursday, and promised part-time operators would be hired full-time to address the operator shortage.

“We apologize and want to let you know what we’re doing about it,” the agency wrote.

The SFMTA has left buses in depots cold, sitting undriven, as scheduled runs are missed across The City, the San Francisco Examiner revealed in an investigation late last month. Muni riders have waited 20 to 40 minutes for buses that usually arrive in just ten minutes, or even sooner.

The cause of the problem is an operator shortage, the public records requested by the Examiner revealed. That’s not just a shortage of new hires, but the result of a training backlog within the agency. The two-month long Twin Peaks tunnel shutdown also played a role in the Muni service slowdown, as bus substitutes replacing the K, L and M train lines took vitally needed bus operators off their normal routes across San Francisco. A notice posted to Muni operators in SFMTA’s Kirkland bus yard, which was obtained by Mission Local, read “18 runs that may be canceled on any given day in order to provide support for the Twin Peaks 60-day shutdown.”

The SFMTA said it will take 60 of its part-time operators and make them full time employees, which will add nearly 700 hours of additional driving service daily. If the SFMTA is indeed able to achieve that level of service, it would go a long way to making up the 860 service hours missed daily in July.

That measurement is a bit technical, but it may help to imagine one run of the 38-Geary from downtown to Sutro Heights, which is about an hour. Now picture similar runs missed 860 times across The City every day, out of a total 9,700 scheduled service hours.

“There’s service being missed everywhere,” John Haley, head of Muni operations at SFMTA, told the Examiner last month.

Vallie Brown, a member of the Board of Supervisors, has called for a hearing into the missed runs issue that will likely take place in September. Brown said, in a statement, “I am heartened to see SFMTA has acknowledged the problems and is taking steps to address them. I look forward to working with the agency to find ways to help it continue to serve the residents of San Francisco.”

In a web post Thursday, SFMTA also committed to increasing the size of all its operator training classes “so we can bring more new operators on board more quickly,” and will work to train more operators for its new light rail vehicles by the end of the year. That’s especially important, as SFMTA Director of Transit John Haley told the Examiner that even though bus service may get somewhat better by Aug. 25, when the Twin Peaks tunnel re-opens and substitute buses are no longer needed, the SFMTA may then see a deficit of operators for its trains.

“We are taking these actions right now,” the SFMTA wrote. “As we near the completion of the Twin Peaks Tunnel project, we will continue to make adjustments to increase our service levels.”

It was not immediately clear how soon the fix would take effect, and Muni officials did not immediately respond to a request for comment Friday morning.

If the efforts by SFMTA are not successful, The City will certainly be vocal about it, as riders have taken to social media to lambast the agency during the slowdown.

“Why no inbound 1BX for 20 minutes? I rely on this to get to work and now I’m late,” wrote Twitter user Maria Grimm on July 24. “Seventh straight week of bus-route service cutbacks that @sfmta_muni refuses to acknowledge or fix,” wrote Twitter user Mike Murphy on July 23, as he tweeted a photo of a 27 minute wait for the 38-Geary. “Are there not enough drivers for the new buses @LondonBreed advocated for?,” wrote Twitter user Ashley Moon on July 25. Moon added that a group of 10-15 people were passed by three different buses that morning, causing them to wait 48 minutes for a bus.

Moon added, “I’ve been a loyal Muni rider for years and never experienced so much frustration as I have the last few months.”